Resource exhaustion in OpenBSD OpenSSH

CVE-2015-5600

The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH through 6.9 does not properly restrict the processing of keyboard-interactive devices within a single connection, which makes it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.094 (95.2th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 95th percentile — 95.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2015-5600: held from 0.094 to 0.094.

EPSS over last 30 days · oldest: 0.094 · newest: 0.094 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2015-5600?
CVE-2015-5600 is a high-severity vulnerability in OpenBSD OpenSSH, classified under CWE-264. CVSS score: 8.1/10. Published 2015-08-03.
How severe is CVE-2015-5600?
High severity. CVSS v3 base score is 8.1 out of 10.
Is CVE-2015-5600 known to be exploited?
21 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.